Abstract: In this study, a general scheme for implementation of attitude and velocity algorithm in Strapdown Inertial Navigation System (SINS) under real-time environment was presented. This real-time implementation scheme was formulated in a recursive form using two time-rate executions and utilized integer arithmetic only. The coding of the attitude and velocity algorithm was conducted by a navigation computer (such as DSP or FPGA). It is shown that the general real-time implementation of strapdown attitude and velocity algorithm can be used in strapdown inertial navigation system for any combinations of gyro incremental angle sample of mth minor interval and (m-1)th minor interval.